1. Field of the Invention
This invention relates to privacy communication systems, and particularly to systems in which information is so encoded, as by segmentation and scrambling of segments, as to gain the benefits of very restricted access. It is an object of this invention to provide a new and improved system of this character. It is a further object of this invention to make the meaningful reception of signals transmitted by wire or cable circuits, by radio, or by light beams with or without transmission through fibers, or other means, dependent upon the ability at the receiving station to recognize and react correctly to various changes of the algorithm which is key to restoration of scrambled signals as received to their original character.
2. Description of the Prior Art
Many systems have been described for the sending of scrambled signal transmissions and receiving and unscrambling of the transmission to recover the original signals. Among these prior systems are time-sequence scrambling systems for speech, for example, some of which involve scrambling and descrambling an original analog speech signal such as may be produced by microphone, with or without electronic amplification, and others of which involve digital encoded signal versions. The prior art includes U.S. Pat. Nos. 4,011,408 to Miller, 4,683,586 to Sakamoto et al, and 2,406,350 to Harrison. Note the text in Col. 4, line 56 et seq. of the Harrison patent as follows:
"Let it be assumed that the communicating parties have agreed on the codes that are to be used at a particular time and that perforated cards embodying such codes are in the code boxes at each station in accordance with the present invention. The sending of a start impulse from the contacts of the transmitting station releases all brush segments at all stations when brush 17 is on start segment 23. At each station, a release magnet 30, when energized, releases latch 31 and thereby allows the brushes 17 at all stations to start out on a revolution in phase with each other". U.S. Pat. Nos. 4,268,720 to Olberg et al, 3,225,142 to Schroeder and 4,221,931 to Seiler are also part of the prior art and contain statements about various prior art systems which said patentees had taken into account. An object of the present invention is to greatly increase the difficulty of trying to determine, and use, a key for successful unauthorized unscrambling of the signals being transmitted.